High speed precessionally switched magnetic logic

ABSTRACT

High speed precessionally switched magnetic logic devices and architectures are described. In a first example, a magnetic logic device includes an input electrode having a first nanomagnet and an output electrode having a second nanomagnet. The spins of the second nanomagnet are non-collinear with the spins of the first nanomagnet. A channel region and corresponding ground electrode are disposed between the input and output electrodes. In a second example, a magnetic logic device includes an input electrode having an in-plane nanomagnet and an output electrode having a perpendicular magnetic anisotropy (PMA) magnet. A channel region and corresponding ground electrode are disposed between the input and output electrodes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/678,877, filed on Nov. 16, 2012, the entire contents of which arehereby incorporated by reference herein.

TECHNICAL FIELD

Embodiments of the invention are in the field of logic devices andarchitectures and, in particular, high speed precessionally switchedmagnetic logic devices and architectures.

BACKGROUND

For the past several decades, the scaling of features in integratedcircuits has been a driving force behind an ever-growing semiconductorindustry. Scaling to smaller and smaller features enables increaseddensities of functional units on the limited real estate ofsemiconductor chips. For example, shrinking transistor size allows forthe incorporation of an increased number of memory devices on a chip,lending to the fabrication of products with increased capacity. Thedrive for ever-more capacity, however, is not without issue. Thenecessity to optimize the performance of each device becomesincreasingly significant.

The operation of spin torque devices is based on the phenomenon of spintransfer torque. If a current is passed through a magnetization layer,called the fixed magnetic layer, it will come out spin polarized. Withthe passing of each electron, its spin (which is angular momentum of theelectron) will be added to the magnetization in a next magnetic layer,called the free magnetic layer, and will cause its small change. Thisis, in effect, a torque-causing precession of magnetization. Due toreflection of electrons, a torque is also exerted on the magnetizationof an associated fixed magnetic layer. In the end, if the currentexceeds a certain critical value (given by damping caused by themagnetic material and its environment), the magnetization of the freemagnetic layer will be switched by a pulse of current, typically inabout 1 nanosecond. Magnetization of the fixed magnetic layer may remainunchanged since an associated current is below its threshold due togeometry or due to an adjacent anti-ferromagnetic layer.

However, significant improvements are still needed in the speed andenergy required for switching of magnetization. Herein is described suchimprovements by way of precessionally switched magnetic logic devicesand architectures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a top view of a spin logic element having collinearmagnets at the input and output of the spin logic element.

FIG. 1B illustrates a top view of a spin logic element havingnon-collinear magnets at the input and output of the spin logic element,in accordance with an embodiment of the present invention.

FIG. 2A illustrates a cross-sectional view of a spin logic device havingcollinear magnets, such as the collinear magnets described inassociation with FIG. 1A.

FIG. 2B illustrates both a top view and a cross-sectional view of a spinlogic device having non-collinear magnets, such as the non-collinearmagnets described in association with FIG. 1B, in accordance with anembodiment of the present invention.

FIG. 3 illustrates the cross-sectional view of the spin logic devicehaving non-collinear magnets of FIG. 2B along with an operationinvolving a non-inverting gate scenario, in accordance with anembodiment of the present invention.

FIG. 4 illustrates both a top view and a cross-sectional view of a spinlogic device having a combination of perpendicular magnetic anisotropy(PMA) and in-plane magnets, in accordance with another embodiment of thepresent invention.

FIG. 5 illustrates a stack 500 of precessional spin logic devices, inaccordance with an embodiment of the present invention.

FIG. 6 is an equivalent spin circuit diagram for a spin logic device, inaccordance with an embodiment of the present invention.

FIG. 7 is a plot of magnetic moment (projection along x-axis) or Voltage(mV) as a function of time (ns) showing simulated response of aprecessionally switched spin logic device at a 5 GHz operatingconditions, in accordance with an embodiment of the present invention.

FIG. 8 includes three-dimensional plots showing magnetic momenttrajectory for nanomagnets, in accordance with an embodiment of thepresent invention.

FIG. 9 illustrates a cross-sectional view of a material stack for a spinlogic device, in accordance with an embodiment of the present invention.

FIG. 10 illustrates a computing device in accordance with oneimplementation of the invention.

DESCRIPTION OF THE EMBODIMENTS

High speed precessionally switched magnetic logic devices andarchitectures are described. In the following description, numerousspecific details are set forth, such as specific magnetic layerintegration and material regimes, in order to provide a thoroughunderstanding of embodiments of the present invention. It will beapparent to one skilled in the art that embodiments of the presentinvention may be practiced without these specific details. In otherinstances, well-known features, such as integrated circuit designlayouts, are not described in detail in order to not unnecessarilyobscure embodiments of the present invention. Furthermore, it is to beunderstood that the various embodiments shown in the Figures areillustrative representations and are not necessarily drawn to scale.

One or more embodiments described herein are directed to high speedprecessionally switched devices, such as magnetic logic devices.Embodiments may include, or may be relevant to or for, one or more ofaugmented complimentary metal oxide semiconductor (CMOS) architectures,instantly on-normally off logic architectures, magnetic embedded memory,magnetic tunnel junction (MTJ) based devices, non-volatile logic, orspin logic. In a specific embodiment, described in greater detail below,a high-speed spin logic device employs non-collinear magnets to enable10 GHz operation.

Embodiments described herein may enable fabrication of fast andnon-volatile logic devices and gates or grounds. By way of contrast,previous approaches to fabricating such devices and to achievenon-volatility have included forming nodes from nanoscale ferromagnets(nanomagnets). The ferromagnets are switched by a spin-polarized currentflowing between an input and an output nanomagnet and, thus, exertingspin torque. In past approaches, the magnetization, which is determinedby the shape of the ferromagnet, has been collinear in all nanomagnets.Therefore, the initial spin torque is zero, and circuits including suchelements rely on thermal fluctuations of magnetization to begin aswitching event. However, an initial spin torque is zero may impactswitching speed and lead to performance variability. For example, thespeed of switching such devices may be slow. Additionally, or instead,timing for switching initiation may vary and be sensitive to devicevariability.

In order to address the above described issues with previous approaches,one or more embodiments described herein are directed to spin logicdevices having non-collinear magnets at the input and output of aswitching element. In one embodiment, such an arrangement permitsnon-zero torque at the start or initiation of switching. Specific suchembodiments include a performance improvement in speed enabling clockingoperation of logic, e.g., less than 100 ps or approximately 10 GHzclocking operation. Other specific such embodiments, enable overcomingreliance on thermal noise to initiate the switching.

By way of illustration, FIG. 1A illustrates a top view of a spin logicelement having collinear magnets at the input and output of the spinlogic element. Referring to FIG. 1A, a spin logic element 100A includesan input 102A, a ground electrode region 104A and an output 106A. Theinput 102A and output 106A each include a ferromagnetic layer(nanomagnet) having a width (Wm). As represented by the rectangulargeometry of the input 102A and output 106A, spins of the ferromagneticlayers of the input 102A and output 106A are collinear. It is notedthat, throughout, the ground terminal is depicted closer to the leftmagnet (102A) than to the right magnet (106A), as may be needed forisolation of input from output.

In contrast to the conventional arrangement of FIG. 1A, FIG. 1Billustrates a top view of a spin logic element having non-collinearmagnets at the input and output of the spin logic element, in accordancewith an embodiment of the present invention. Referring to FIG. 1B, aspin logic element 100B includes an input 102B, a ground electroderegion 104B and an output 106B. The input 102B and output 106B eachinclude a ferromagnetic layer (nanomagnet) having a width (Wm). However,as represented by the elliptic geometries of the input 102B and output106B, which are non-parallel, spins of the ferromagnetic layers of theinput 102B and output 106B are non-collinear. In one such embodiment,such an arrangement of non-collinear magnets enables high speed spinlogic.

By way of further illustration, FIG. 2A illustrates a cross-sectionalview of a spin logic device having collinear magnets, such as thecollinear magnets described in association with FIG. 1A. Referring toFIG. 2A, a spin logic device 200A includes a supply voltage plane 201Acoupled with an input 202A and an output 206A. The input 202A and output206A each include a ferromagnetic layer (nanomagnet), such as layers203A and 207A, respectively. A ground electrode 204A is disposed betweenthe input 202A and the output 206A. A metal ground line 208A may becoupled with the ground electrode 204A, as depicted in FIG. 2A.Additional materials, such as oxide layer 210A may also be included,e.g., to act as a spin filter.

Referring again to FIG. 2A, an operation involving a non-inverting gatescenario 212A is shown for a plurality of input spin states 214A havinga net spin direction 216A. The dominant magnet injects spin into theoutput, forcing the output to align, as represented by arrows 218A and219A. Thus, a plurality of output spin states 220A having a net spindirection 222A is obtained. As represented by the horizontal depictionof the plurality of input spin states 214A and the plurality of outputspin states 220A, the spins of the pluralities 214A and 220A arecollinear.

In contrast to the conventional arrangement of FIG. 2A, FIG. 2Billustrates both a top view and a cross-sectional view of a spin logicdevice having non-collinear magnets, such as the non-collinear magnetsdescribed in association with FIG. 1B, in accordance with an embodimentof the present invention. Referring to FIG. 2B, a spin logic device 200Bincludes a supply voltage plane 201B coupled with an input 202B and anoutput 206B. The input 202B and output 206B each include a ferromagneticlayer (nanomagnet), such as layers 203B and 207B, respectively, having athickness T_(m), width W_(m) and length L_(m). A ground electrode (orregion, as shown as a dashed line in the top view) 204B is disposedbetween the input 202B and the output 206B and has a ground length L_(G)and ground thickness T_(G). A corresponding channel region 250B has achannel length L_(C) and thickness T_(C). A metal ground line 208B maybe coupled with the ground electrode 204B, as depicted in FIG. 2B.Additional materials, such as oxide layer 210B may also be included,e.g., to act as a spin filter. As described in association with FIG. 1B,spins of the ferromagnetic layers of the input 202B and output 206B,i.e. of magnetic layers 203B and 207B, are non-collinear, as is alsodepicted in the top view of FIG. 2B.

FIG. 3 illustrates the cross-sectional view of the spin logic devicehaving non-collinear magnets of FIG. 2B along with an operationinvolving a non-inverting gate scenario, in accordance with anembodiment of the present invention. Referring to FIG. 3, an operationinvolving a non-inverting gate scenario 312 is shown for a plurality ofinput spin states 314 having an angular net spin direction 316corresponding to a net spin direction 317. The dominant magnet injectsspin into the output, forcing the output to align, as represented byarrows 318 and 319. Thus, a plurality of output spin states 320 havingan angular net spin direction 322, corresponding to a net spin direction323, is obtained. As represented by the angular depiction of theplurality of input spin states 314 and the plurality of output spinstates 320 In FIG. 3, the spins of the plurality 314 are non-collinearwith the spins of the plurality 320. As such, operation of theprecessionally switched magnetic logic device of FIG. 3 involves flow ofspin due to asymmetry in spin populations, as shown. A net perpendiculartorque from the input magnet dominates the output magnet dynamics.

Referring again to FIGS. 1B, 2B and 3, one or more embodiments include aspin logic device operating via precessional switching of nanomagnets.The precessional switching dynamics is achieved by a non-collinearmagnet configuration. In one such embodiment, input and output magnetsare tilted at approximately 45°, in opposite directions, with respect tothe channel direction. The non-collinearity produces a strong spintorque from the beginning of the nanomagnet dynamics, resulting in afaster response. Traditional spin logic devices, such as those describedin association with FIGS. 1A and 2A, employ collinear magnets, whichproduce no torque at the initial time when the voltage is applied. Insuch traditional spin logic devices, the magnets eventually startswitching in response to thermal noise.

In an embodiment, planar magnets are used and operated with precessionalswitching, e.g., as described for the precessional switching spin logicdevice of FIG. 3. The elliptic magnets (seen in the top view of FIG. 2B)allow for control of the direction of magnetization by using shapeanisotropy. In a specific such embodiment, the shape anisotropy isachieved by rotation of a planar magnet greater than 0 degrees but lessthan 45 degrees to provide a rectangular shape with rounded corners.Stable equilibria occur when magnetization is directed along the major(longest) axis of the ellipses, as defined by patterning of the magneticmaterial. The major axes of the input and output magnets are pointed atapproximately 90 degrees with respect to one other. In an embodiment,such an arrangement maximizes an applied spin torque at the initialinstant, in contrast to a collinear device. The stability of the finalstate is ensured by applying a pulse of voltage necessary to switch themagnetization proximate to the opposite direction. Subsequently, themagnets relax into a stable equilibrium.

In an embodiment, the structure described in association with FIGS. 2Band 3 are fabricated using multiple stacked metallic layers. The magnetsare formed from thin patterned ferromagnetic metals. A metallic channel,formed by a wire etched in a copper layer (e.g., for long spin diffusionlength), may be used to couple the input and output magnets in order toconduct spin current from the input magnet to the output magnet. A metalvia may be used to couple the channel region to a ground plane. Thedimensions of the ground plane may be selected to optimize theenergy-delay of the device.

Overall, in an embodiment, the directionality of spin logic is set bythe geometric asymmetry in the device. The area of overlap of the inputmagnet with the channel is larger than the area of overlap of the outputmagnet. This difference in overlap leads to asymmetric spin conductionwhere the input magnet sets up the direction of the spin currents in thechannel. In a specific embodiment, an oxide gap in the channel permitsisolation of the input and output side of the magnets.

In another aspect, perpendicular magnetic anisotropy (PMA) may be usedto enhance the switching speed of a magnetic logic device. For example,in an embodiment, in-plane and PMA magnets are combined to produceprecessional switching, providing an alternate device scheme from thatdescribed in association with FIG. 3. Specifically, a structure forprecessionally switched spin logic may employ both perpendicular magnetsand in-plane magnets, e.g., by using an in-plane magnet for an input andPMA magnet for an output. The direction of magnetization is set by theinterplay between the PMA of the magnetic material along with themagnetic layer thickness. In one embodiment, such an approach permitsmore facile fabrication processing and magnetic annealing methods than,e.g., the use of two materials and magnetizing anneal steps. It is to beunderstood, however, the operating principles for the PMA/in-planeprecessional magnets arrangements are similar to those described for thenon-collinear arrangements shown in FIGS. 1B, 2B and 3.

As an example, FIG. 4 illustrates both a top view and a cross-sectionalview of a spin logic device having a combination of perpendicularmagnetic anisotropy (PMA) and in-plane magnets, in accordance withanother embodiment of the present invention. Referring to FIG. 4, a spinlogic device 400 includes a supply voltage plane 401 coupled with aninput 402 and an output 406. The input 402 and output 406 each include aferromagnetic layer (nanomagnet), such as layers 403 and 407,respectively. However, the ferromagnetic layer 403 provides an in-planemagnet having a length L_(m). Meanwhile, the ferromagnetic layer 403provides a PMA magnet having a thickness T_(m) and width W_(m). Asindicated by arrows 460 and 462 and the feature 470, the direction ofthe magnets are orthogonal to one another. It is to be understood that,in another embodiment, the input may include a PMA magnet while theoutput includes an in-plane magnet. A ground electrode (or region, asshown as a dashed line in the top view) 404 is disposed between theinput 402 and the output 406 and has a ground length L_(G) and groundthickness T_(G). A corresponding channel region 450 has a channel lengthL_(C) and thickness T_(C). A metal ground line 408 may be coupled withthe ground electrode 404, as depicted in FIG. 4, providing ground at thecenter of the device 400. Additional materials, such as oxide layer 410may also be included, e.g., to act as a spin filter.

In another aspect, precessional spin logic devices may be stacked forincreasing logic density. As an example, FIG. 5 illustrates a stack 500of precessional spin logic devices, in accordance with an embodiment ofthe present invention. Referring to FIG. 5, a first stack 502, secondstack 504 and third stack 506 of spin logic devices is included instructure 500. Metals ground planes 508 and 510 and voltage supplyplanes 512 and 514 are arranged in an alternating fashion. Magneticlayers 516, 518, 520, 522, and 524 along with other layers such as oxidelayer 526 and 528 are also included. In the arrangement 500, out ofplane spin currents 530 and coupled with an interconnect repeater 532,providing alternate magnetic layers magnetized in the same orientation,allowing for signal flow.

The structure 500 may be described as three-dimensional logic havingstacked alternating spin logic (ASL) logic layers. The information flowin such an arrangement is ensured by using alternate layers of magnetsaligned as shown. The direction of the magnets can be set by the shapeof the patterned layers and can be controlled to obtain appropriatealignment.

In another aspect, numerical simulations of an all spin interconnectwith self-consistent micromagnetic dynamics and spin transport areprovided to illustrate operational aspects of one or more embodimentsdescribed herein. For example, a theoretical treatment and numericalsimulations of the repeated all spin interconnect show its operationusing a multi-physics simulation which treats the nanomagnets as singlemagnetic moments and uses spin circuit theory to calculate the scalarvoltage and vector spin voltages. An equivalent circuit 600 for asection of the spin interconnects is shown in FIG. 6, in accordance withan embodiment of the present invention. Referring to FIG. 6, nodes 1 and2 are representative of the contact point of the magnets with thechannel. Nodes 4, 5, 7 are the internal nodes of the channel toaccommodate for spin flip current. Node 6 is the point of contact of theground connection with the spin channel.

The dynamics of nanomagnets may be described by Landau-Lifshitz-Gilbertequations (1) and (2):

$\begin{matrix}{\frac{\partial m_{1}}{\partial t} = {{- {{\gamma\mu}_{0}\left\lbrack {m_{1} \times H_{eff}} \right\rbrack}} + {\alpha \left\lbrack {m_{1} \times \frac{\partial m_{1}}{\partial t}} \right\rbrack} + \frac{I_{s\; 1}}{{eN}_{s}}}} & (1) \\{\frac{\partial m_{2}}{\partial t} = {{- {{\gamma\mu}_{0}\left\lbrack {m_{2} \times H_{eff}} \right\rbrack}} + {\alpha \left\lbrack {m_{2} \times \frac{\partial m_{2}}{\partial t}} \right\rbrack} + \frac{I_{s\; 2}}{{eN}_{s}}}} & (2)\end{matrix}$

Here, Is1 and Is2 are the projections perpendicular to magnetizations ofthe spin polarized currents entering the nanomagnets. The projectionsare derived from the spin-circuit analysis. The effective magnetic fieldHeff originating from shape and material anisotropy, and the Gilbertdamping constant a are the properties of the magnets.

The spin currents may be obtained from the transport model shown in FIG.7, which is a plot 700 of magnetic moment (X) or Voltage (mV) as afunction of time (ns) showing simulated response of the precessionallyswitched spin logic device at a 5 GHz operating conditions, inaccordance with an embodiment of the present invention. The spinequivalent circuit includes the tensor spin conduction matrix determinedby the instantaneous direction of magnetization. A self-consistentstochastic solver is used to account for thermal noise in the magnets.FIG. 8 includes three-dimensional plots 802 and 804 showing magneticmoment trajectory for the nanomagnets, in accordance with one or moreembodiments of the present invention.

Overall, we have described and experimentally demonstrated the primaryphysical phenomena for precessionally switched magnetic logic devices.In an embodiment, a manufacturing flow and materials used to fabricatesuch devices is the same or highly compatible with processes used tofabricate spin torque transfer (STT)-RAM. As such, one or moreembodiments provide an approach for fabricating low power spin logictechnology while leveraging manufacturing capability used for STT-RAMmanufacturing. The long length of propagation of spin polarized currentsand their ability to switch nanomagnets have also been demonstrated.

Although the method of fabricating a stack of layers for aprecessionally switched magnetic logic device or architecture has notbeen described in detail herein, it is to be understood that theoperations for fabrication may include standard microelectronicfabrication processes such as lithography, etch, thin films deposition,planarization (such as chemical mechanical polishing (CMP)), diffusion,metrology, the use of sacrificial layers, the use of etch stop layers,the use of planarization stop layers, and/or any other action associatedwith microelectronic component fabrication.

In order to provide an exemplary stack of materials suitable formanufacture of devices described herein, FIG. 9 illustrates across-sectional view of a material stack for a spin logic device, inaccordance with an embodiment of the present invention.

Referring to FIG. 9, magnets 902 and 904 may be elemental, based on analloy, or based on a half-metal material. For example, in oneembodiment, magnets 902 and 904 are composed of an elemental materialsuch as, but not limited to, iron (Fe), cobalt (Co), nickel (Ni), orgadolinium (Gd, <290K). In one embodiment, magnets 902 and 904 arecomposed of an alloy material such as, but not limited to, cobalt iron(Co_(x)Fe_(y)), nickel cobalt (Ni_(x)Co_(y)), nickel iron(Ni_(x)Fe_(y)), cobalt iron boron (Co_(x)Fe_(y)B_(z)), samarium cobalt(Sm_(x)Co_(y)), or neodymium iron boron (Nd_(x)Fe_(y)B_(z)). In oneembodiment, magnets 902 and 904 are composed of a Heusler Alloy (halfmetal) material such as, but not limited to, copper manganese aluminum(Cu₂MnAl), copper manganese indium (Cu₂MnIn), copper manganese tin(Cu₂MnSn), copper iron silicon (Co₂FeSi), cobalt iron aluminum(Co₂FeAl), or gallium manganese (GaMn). The Heusler Alloys areferromagnetic metal alloys based on a Heusler phase. Heusler phases maybe intermetallics with particular composition and face-centered cubiccrystal structure. The materials are ferromagnetic, even though theconstituting elements are not, as a result of the double-exchangemechanism between neighboring magnetic ions. The materials usuallyinclude manganese ions, which sit at the body centers of the cubicstructure and carry most of the magnetic moment of the alloy.

Referring again to FIG. 9, spin filter layer 906 may be composed of anoxide layer. In on such embodiment, spin filter layer 906 is composed ofa material such as but not limited to, magnesium oxide (MgO), aluminumoxide (Al₂O₃), or europium oxide (EuO). In an embodiment, spin filterlayer 906 is composed of a material suitable for allowing current of amajority spin to pass through the layer, while impeding at least to someextent current of a minority spin to pass through the layer.

Referring again to FIG. 9, channel region 908 may be composed of anelemental material or an alloy. In one such embodiment, channel region908 is composed of an elemental material such as, but not limited to,copper (Cu) or aluminum (Al). In another such embodiment, channel region908 is composed of an alloy material such as, but not limited to, coppersilicon (CuSi) or copper germanium (CuGe). Pin layers may also beincluded and, in one embodiment, are composed of an alloy such as, butnot limited to, iridium manganese (IrMn), chromium (Cr) based materials,or platinum manganese (PtMn). The pin layers may provide a permanentmagnetization.

Other layers for inclusion may include elemental spin hall layers, suchas elemental layers. In one embodiment, one or more spin hall layers iscomposed of platinum (Pt), tantalum (Ta), doped copper (Cu), or gold(Au). Elemental scrambler layers may also be included. In oneembodiment, one or more scrambler layers is composed of elementalruthenium (Ru). Metal ground 910 and supply voltage planes 1012 may becomposed of conductive materials such as, but not limited to, copper(Cu).

The direction of magnetization in the magnets 902 and 904 may beswitched using a spin-polarized current. An electrical current isgenerally non-polarized (e.g. consisting of about 50% spin-up and about50% spin-down electrons). A spin polarized current is one with a greaternumber of electrons of either spin-up or spin-down. In operation, in anembodiment, if an applied voltage is negative, the spin of the output isa copy of the spin of the input (e.g., input 302 and output 306 of FIG.3). However, if the applied voltage of positive, the spin of the outputis a mirror of the spin of the input. Generally, it is to be understoodthat initial or final logic states are a ferro-magnet's domain and thedomain is manipulated and/or controlled by a spin current.

FIG. 10 illustrates a computing device 1000 in accordance with oneimplementation of the invention. The computing device 1000 houses aboard 1002. The board 1002 may include a number of components, includingbut not limited to a processor 1004 and at least one communication chip1006. The processor 1004 is physically and electrically coupled to theboard 1002. In some implementations the at least one communication chip1006 is also physically and electrically coupled to the board 1002. Infurther implementations, the communication chip 1006 is part of theprocessor 1004.

Depending on its applications, computing device 1000 may include othercomponents that may or may not be physically and electrically coupled tothe board 1002. These other components include, but are not limited to,volatile memory (e.g., DRAM), non-volatile memory (e.g., ROM), flashmemory, a graphics processor, a digital signal processor, a cryptoprocessor, a chipset, an antenna, a display, a touchscreen display, atouchscreen controller, a battery, an audio codec, a video codec, apower amplifier, a global positioning system (GPS) device, a compass, anaccelerometer, a gyroscope, a speaker, a camera, and a mass storagedevice (such as hard disk drive, compact disk (CD), digital versatiledisk (DVD), and so forth).

The communication chip 1006 enables wireless communications for thetransfer of data to and from the computing device 1000. The term“wireless” and its derivatives may be used to describe circuits,devices, systems, methods, techniques, communications channels, etc.,that may communicate data through the use of modulated electromagneticradiation through a non-solid medium. The term does not imply that theassociated devices do not contain any wires, although in someembodiments they might not. The communication chip 1006 may implementany of a number of wireless standards or protocols, including but notlimited to Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16 family), IEEE802.20, long term evolution (LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE,GSM, GPRS, CDMA, TDMA, DECT, Bluetooth, derivatives thereof, as well asany other wireless protocols that are designated as 3G, 4G, 5G, andbeyond. The computing device 1000 may include a plurality ofcommunication chips 1006. For instance, a first communication chip 1006may be dedicated to shorter range wireless communications such as Wi-Fiand Bluetooth and a second communication chip 1006 may be dedicated tolonger range wireless communications such as GPS, EDGE, GPRS, CDMA,WiMAX, LTE, Ev-DO, and others.

The processor 1004 of the computing device 1000 includes an integratedcircuit die packaged within the processor 1004. In some implementationsof the invention, the integrated circuit die of the processor includesone or more devices, such as high speed precessionally switched magneticlogic devices built in accordance with implementations of the invention.The term “processor” may refer to any device or portion of a device thatprocesses electronic data from registers and/or memory to transform thatelectronic data into other electronic data that may be stored inregisters and/or memory.

The communication chip 1006 also includes an integrated circuit diepackaged within the communication chip 1006. In accordance with anotherimplementation of the invention, the integrated circuit die of thecommunication chip includes one or more devices, such as high speedprecessionally switched magnetic logic devices built in accordance withimplementations of the invention.

In further implementations, another component housed within thecomputing device 1000 may contain an integrated circuit die thatincludes one or more devices, such as high speed precessionally switchedmagnetic logic devices built in accordance with implementations of theinvention.

In various implementations, the computing device 1000 may be a laptop, anetbook, a notebook, an ultrabook, a smartphone, a tablet, a personaldigital assistant (PDA), an ultra mobile PC, a mobile phone, a desktopcomputer, a server, a printer, a scanner, a monitor, a set-top box, anentertainment control unit, a digital camera, a portable music player,or a digital video recorder. In further implementations, the computingdevice 1000 may be any other electronic device that processes data.

Thus, embodiments of the present invention high speed precessionallyswitched magnetic logic devices and architectures.

In an embodiment, a magnetic logic device includes an input electrodehaving a first nanomagnet and an output electrode having a secondnanomagnet. The spins of the second nanomagnet are non-collinear withthe spins of the first nanomagnet. A channel region and correspondingground electrode are disposed between the input and output electrodes.

In one embodiment, the magnetic logic device further includes a metalground line coupled to the ground electrode.

In one embodiment, the magnetic logic device further includes a supplyvoltage plane coupled with one or both of the first and secondelectrodes.

In one embodiment, one or both of the nanomagnets is composed of anelemental material such as, but not limited to, iron (Fe), cobalt (Co),nickel (Ni), or gadolinium (Gd).

In one embodiment, one or both of the nanomagnets is composed of analloy material such as, but not limited to, cobalt iron (Co_(x)Fe_(y)),nickel cobalt (Ni_(x)Co_(y)), nickel iron (Ni_(x)Fe_(y)), cobalt ironboron (Co_(x)Fe_(y)B_(z)), samarium cobalt (Sm_(x)Co_(y)), or neodymiumiron boron (Nd_(x)Fe_(y)B_(z)).

In one embodiment, one or both of the nanomagnets is composed of aHeusler Alloy material such as, but not limited to, copper manganesealuminum (Cu₂MnAl), copper manganese indium (Cu₂MnIn), copper manganesetin (Cu₂MnSn), copper iron silicon (Co₂FeSi), cobalt iron aluminum(Co₂FeAl), or gallium manganese (GaMn).

In one embodiment, the channel region is composed of a material such as,but not limited to, copper (Cu), aluminum (Al), silver (Ag), gold (Au),a monolayer of graphene, multi-layered graphene, or silicon, germanium,or silicon germanium alloys thereof.

In one embodiment, the magnetic logic device further includes a spinfilter dielectric layer disposed adjacent to at least a portion of thechannel region.

In one embodiment, the spin filter dielectric layer is composed of amaterial such as, but not limited to, magnesium oxide (MgO), aluminumoxide (Al₂O₃), mono or multilayered graphene (C), or europium oxide(EuO).

In an embodiment, a method of operating a magnetic logic device includesproviding current having a net spin direction from an input electrodehaving a first nanomagnet to a ground channel region of the device. Thecurrent is received at an output electrode having a second nanomagnet toalign the spins of the second nanomagnet. The spins of the secondnanomagnet non-collinear with the spins of the first nanomagnet.

In one embodiment, providing the current from the input electrode andreceiving the current at the output electrode is for precessionallyswitching the device.

In one embodiment, initiation of the precessional switching of thedevice involves using non-zero spin torque.

In one embodiment, providing the current from the input electrode andreceiving the current at the output electrode involves non-inversiongating of the channel region.

In one embodiment, the non-inversion gating includes using a negativesupply voltage.

In one embodiment, providing the current from the input electrode andreceiving the current at the output electrode includes inversion gatingof the channel region.

In one embodiment, the inversion gating includes using a positive supplyvoltage.

In an embodiment, a magnetic logic device includes an input electrodehaving an in-plane nanomagnet and an output electrode having aperpendicular magnetic anisotropy (PMA) magnet. A channel region andcorresponding ground electrode are disposed between the input and outputelectrodes.

In one embodiment, the magnetic logic device further includes a metalground line coupled to the ground electrode.

In one embodiment, the magnetic logic device further includes a supplyvoltage plane coupled with one or both of the first and secondelectrodes.

In one embodiment, one or both of the in-plane nanomagnet and the PMAmagnet is composed of an elemental material such as, but not limited to,iron (Fe), cobalt (Co), nickel (Ni), gadolinium Gd, or atomicmultilayers thereof.

In one embodiment, iron (Fe), cobalt (Co), nickel (Ni), or gadolinium(Gd) atomic multilayers are used, and are interspersed with nonmagneticinterlayers composed of palladium (Pd) or platinum (Pt).

In one embodiment, one or both of the in-plane nanomagnet and the PMAmagnet is composed of an alloy material such as, but not limited to,cobalt iron (Co_(x)Fe_(y)), nickel cobalt (Ni_(x)Co_(y)), nickel iron(Ni_(x)Fe_(y)), cobalt iron boron (Co_(x)Fe_(y)B_(z)), samarium cobalt(Sm_(x)Co_(y)), or neodymium iron boron (Nd_(x)Fe_(y)B_(z)).

In one embodiment, one or both of the in-plane nanomagnet and the PMAmagnet is composed of a Heusler Alloy material such as, but not limitedto, copper manganese aluminum (Cu₂MnAl), copper manganese indium(Cu₂MnIn), copper manganese tin (Cu₂MnSn), copper iron silicon(Co₂FeSi), cobalt iron aluminum (Co₂FeAl), or gallium manganese (GaMn).

In one embodiment, the magnetic logic device further includes a spinfilter dielectric layer disposed adjacent to at least a portion of thechannel region.

In one embodiment, the spin filter dielectric layer is composed of amaterial such as, but not limited to, magnesium oxide (MgO), aluminumoxide (Al₂O₃), or europium oxide (EuO).

In one embodiment, a method of operating a magnetic logic deviceincludes providing current having a net spin direction from an inputelectrode having an in-plane nanomagnet to a ground channel region ofthe device. The current is received at an output electrode having aperpendicular magnetic anisotropy (PMA) magnet to align the spins of thePMA magnet.

In one embodiment, providing the current from the input electrode andreceiving the current at the output electrode precessionally switchesthe device.

In one embodiment, providing the current from the input electrode andreceiving the current at the output electrode involves non-inversiongating of the channel region.

In one embodiment, the method further includes pulsing a supply voltageto obtain optimal energy operation of the device.

In one embodiment, pulsing the supply voltage includes using a pulsewidth selected for minimum charge injection from the supply voltage.

What is claimed is:
 1. A magnetic logic device, comprising: an inputelectrode comprising a first nanomagnet; an output electrode comprisinga second nanomagnet, the spins of the second nanomagnet non-collinearwith the spins of the first nanomagnet; and a channel region andcorresponding ground electrode disposed between the input and outputelectrodes, wherein the first nanomagnet has an elliptical shape with amajor axis and a minor axis, and the second nanomagnet has an ellipticalshape with a major axis and a minor axis, and wherein the major axis ofthe first nanomagnet is oriented approximately 90 degrees to the majoraxis of the second nanomagnet.
 2. The magnetic logic device of claim 1,further comprising: a metal ground line coupled to the ground electrode.3. The magnetic logic device of claim 1, further comprising: a supplyvoltage plane coupled with one or both of the first and secondelectrodes.
 4. The magnetic logic device of claim 1, wherein one or bothof the nanomagnets comprises an elemental material selected from thegroup consisting of iron (Fe), cobalt (Co), nickel (Ni), and gadolinium(Gd).
 5. The magnetic logic device of claim 1, wherein one or both ofthe nanomagnets comprises an alloy material selected from the groupconsisting of cobalt iron (Co_(x)Fe_(y)), nickel cobalt (Ni_(x)Co_(y)),nickel iron (Ni_(x)Fe_(y)), cobalt iron boron (Co_(x)Fe_(y)B_(z)),samarium cobalt (Sm_(x)Co_(y)), and neodymium iron boron(Nd_(x)Fe_(y)B_(z)).
 6. The magnetic logic device of claim 1, whereinone or both of the nanomagnets comprises a Heusler Alloy materialselected from the group consisting of copper manganese aluminum(Cu₂MnAl), copper manganese indium (Cu₂MnIn), copper manganese tin(Cu₂MnSn), copper iron silicon (Co₂FeSi), cobalt iron aluminum(Co₂FeAl), and gallium manganese (GaMn).
 7. The magnetic logic device ofclaim 1, wherein the channel region comprises a material selected fromthe group consisting of copper (Cu), aluminum (Al), silver (Ag), gold(Au), a monolayer of graphene, multi-layered graphene, and silicon,germanium, or silicon germanium alloys thereof.
 8. The magnetic logicdevice of claim 1, further comprising: a spin filter dielectric layerdisposed adjacent to at least a portion of the channel region.
 9. Themagnetic logic device of claim 8, wherein the spin filter dielectriclayer comprises a material selected from the group consisting ofmagnesium oxide (MgO), aluminum oxide (Al₂O₃), mono or multilayeredgraphene (C), and europium oxide (EuO).
 10. A method of operating amagnetic logic device, the method comprising: providing current having anet spin direction from an input electrode comprising a first nanomagnetto a ground channel region of the device; and receiving the current atan output electrode comprising a second nanomagnet to align the spins ofthe second nanomagnet, the spins of the second nanomagnet non-collinearwith the spins of the first nanomagnet, wherein the first nanomagnet hasan elliptical shape with a major axis and a minor axis, and the secondnanomagnet has an elliptical shape with a major axis and a minor axis,and wherein the major axis of the first nanomagnet is orientedapproximately 90 degrees to the major axis of the second nanomagnet. 11.The method of claim 10, wherein providing the current from the inputelectrode and receiving the current at the output electrode is forprecessionally switching the device.
 12. The method of claim 11, whereininitiation of the precessional switching of the device comprises usingnon-zero spin torque.
 13. The method of claim 10, wherein providing thecurrent from the input electrode and receiving the current at the outputelectrode comprises non-inversion gating of the channel region.
 14. Themethod of claim 13, wherein the non-inversion gating comprising using anegative supply voltage.
 15. The method of claim 10, wherein providingthe current from the input electrode and receiving the current at theoutput electrode comprises inversion gating of the channel region. 16.The method of claim 15, wherein the inversion gating comprising using apositive supply voltage.